One of the main handlers to big-bang is to-draw-page,
which controls how the world is rendered on screen. The first
argument computes a rendering of the world as a DOM tree, and the
second argument computes that tree’s styling.

4.1Jsworld Types

A dom-sexp describes the structure of a web page:

dom-sexp

=

(listdom-elementdom-sexp...)

a css-sexp describes the structure of a page’s styling:

css-sexp

=

(listof(cons(ordom-elementstring)

(listofattrib)))

An attrib is a:

attrib

=

(liststringstring)

Each of the dom-elements can take in an optional attribute list to
assign to the new dom element; the common useful attribute is a key-value binding for an "id",
which can be used to identify an element in the css-drawing function.

Creates an input form element. The types that are currently supported are:

"text"

"password"

"checkbox"

When the user changes the content of the form element, the runtime
uses world-update-f to update the world. If the
type is either "text" or "password", then
the string value of the element will be passed as the second argument
to it. If type is "checkbox", a boolean
representing the checked status of the element will be passed to it.

The example below has a single text input form element, which allows the user to enter
some value.